Albert dtjkand



(No Model.) 2 SheetsSheet 1.

A. DUNANID.

APPARATUS AND SYSTEM FOR T-ELBPHONIG OOMMUNIOATION.

Patented July 3, 1883.

I NVENTQRI WITNESSES:

By his .flttorneys, V

NIPETERS. P'mlo-Lhhcgmphu. Washington, D.

2 Sheets-Sheet 2.

(No Model.)

' A. DUNA-ND.

APPARATUS AND SYSTEM FOR TELEPHONIG GOMMUNIGATION.

Patented July 3, 1883.

WITNESSES:

Mmbf m/mm UNITED PATENT Omen.

ALBERT DUNAND, OF PARIS, FRANCE.

APPARATUS AND SYSTEM" FOR' T'ELEPH-O'INICF COMMUNICATION.

SPECIFICATION forming part of Letters Patent No. 280,365, dated July 3,1883.

Application filed January 9, 1883. (No model.) Patented in FranceDecember 14, 1880, No. 140,133.

To all whom it may concern Be it known that I, ALBERT DUNAND, a citi- Iheard when applied to the ear. due to the intercalation of the battery1? in j the secondary circuit, as it is the polarization zen of theFrench Republic, residing in Paris, France, have invented certainImprovements in Apparatus and Systems for Telephonic Com munication, ofwhich the following is a specification.

The possibility of reproducing sounds by the action of the undulatorycurrent of a micro- IO phone 011 an electric condenser has long beenknown.

My present invention has for its object to reproduce speech by means ofelectric con- 'densers, and in particular singing condensers, so called.To this end I place the condensers on the secondary circuit of aninduction-coil, in which circuit a battery is also in stalled, and inthe primary circuit thereof is included the usual battery andmicrophonic 2o transmitter. Y

Figure l of the accompanying drawings is a diagram showing theelectrical installation of my system. Fig.2 is an elevation of one of mysinging-condensers. Fig. 3 is a transverse section of the same on alarger scale. Fig. 4 is a diagram illustrating the arrangement of theleaves in the condenser. Figs..5 and 6 show the preferred form ofgrouped condensers, each view being a section cut in the plane of thelike-numbered line in the other. Fig.

7 is a horizontal section of a modified form of condenser. Fig. 8 is afront elevation of an other form, and Fig. 9 is a transverse sectionthereof.

Let B in Fig. 1 designate an induction-coil, of which 19 p is thecircuit in connection with the primary wire thereof, and s s the circuitin connection with the secondary wire thereof. In the primary circuit 1)p are installed a bat- 0 tery, I, and a miorophonio transmitter-,M,

and installed it reproduces speechwith perfeet clearness, andsufficiently loud to be easily This result is of the condenser due tothe potential of this battery which renders the condenser capable ofreproducing articulate sounds.

The leaves of tin-foil a a of the condenser are united alternately, twoby two, in such a manner as to form two series, each connected to one ofthe binding-posts I) b, which are mounted on the box 0, in which theleaves are inclosed. In the front of this box is an opening, e, tofacilitate the escape of the sound. The leaves of tin-foil are separatedfrom each other by the interposition-of sheets of insulating material,

of paraffiuedor varnished paper. These are shown only in Fig. 4, wherethey are denoted by dotted lines, the full lines denoting the leaves offoil. The best arrangement, however, is to use two of these condensers,united in derivation in the circuit 8 s, so that in listening one may beplaced over each ear.

WVhen it is desired to obtain much more intense sounds, which may beheard at some distance, I combine in one box, as shownin Figs. 5 and 6,a number of condensers-say five or. six, or more, if necessary-andconnect them either in series or in derivation, but preferably inderivation. The condensers are an ranged parallel, but slightlyseparated from each other, as shown in Fig. 5, all the armatures on oneside being connected together and joined to one binding-post I), whileall those on the otherside are likewise united and joined to theopposite binding-post. At one side of their inolosing-box A, at a littledistance from the edges of the condensers, is an opening, E, to whichone ear of the listener may be applied, while from a correspondingopening on the opposite side an acoustic tube, F, may be conducted tohis other ear.

they shall touch each other at their rear edges, while their front edgesare separated about a centimeter, after the manner of a fan, as shown inFig. 7 The rear edges may be mounted on a platform or sounding-box, D.Thus constructed, it is not necessary to apply the ear Another arrange--ment consists in placing the condensers so that loid, metal, &c.--whichmay be pierced with a central opening or not, as desired.

My system is not restricted in its application to the precise detailsand methods herein set forth and shown, but may be applied to batteries,microphones, and condensers of any kind, size, or shape.

I claim as my invention- 1. The improved system of telephonicallytransmitting sound, which consists of the conibination of aninduction-coil, a primary circuit including the primary wire thereof, amicrophonic transmitter and a battery, both included in said circuit, asecondary circuit including the secondary wire of said coil, and abattery and condenser, both included in said secondary circuit,substantially as set forth.

2. The combination, to form a receiving-telephone, of severalsinging-condensers grouped together, with intervening spaces tofacilitate the escape of sound, and with the opposite armatures of allthe condensers connected with opposite terminals, substantially as setforth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

ALBERT DUN AND.

Witnesses:

R0121. M. HOOPER, AMAND BITTER.

